Wear-free electromagnetic and permanent magnetic eddy current and hysteresis brakes have already become known which are preferably provided with poles of alternate polarity in the direction of motion and serve the purpose of slowing down or decelerating the speed of high-speed track-bound vehicles. With the above referred to brakes, magnetic fields result due to the eddy currents generated in the track. These magnetic fields counteract the magnetic fields of the brake and thus produce considerable braking forces, especially at high speeds. At the same time the attractive force is reduced between track and brake.
At decreasing speeds the generation of eddy currents in the track is reduced so that their effect with respect to braking weakens. At low speeds considerable attractive forces result between track and brake because of the disappearing magnetic counterfields. These attractive forces try to press the eddy current brake onto the track.
For a long time magnetically operating friction brakes also have been known. With such brakes a braking or wearing element is pressed against the ferromagnetic track by means of magnetic attractive forces. Due to the resulting friction, a good braking effect is achieved. Because of the high wear this type of brake is less suitable for continuous braking operations at high speed.
A variable permanent magnetic brake with poles of alternate polarity, preferably in the direction of motion, can also be designed such that it operates as an almost wear-free eddy current or hysteresis brake at high speeds and as friction brake at low speeds. However, the change from eddy current to friction braking involves difficulties since in many cases braking by frictional forces results in sudden high decelerating forces.